JP2002202392A - Nuclear transformation device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transform nuclear species with a relatively small device. SOLUTION: The device 10 causing nuclear transformation is constituted by providing a nearly plate shape structure 11 made of palladium (Pd) or alloy of Pd, or other metals (Ti and the like for example) occluding hydrogen and a material 14 adhered to one surface 11A of the structure 11 sides which causes nuclear transformation. If one surface 11A side of the structure 11 is made a region 12 with higher deuterium pressure by pressurization or electrolysis and the like and the other surface 11B side is made a region 13 with lower deuterium pressure by vacuum exhaust and the like, a flow 15 of deuterium is produced in the structure 11 and nuclear transformation is caused by the reaction of deuterium and the material 14 causing nuclear transformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radionuclide conversion apparatus for converting a long-lived radioactive waste into a short-lived nuclide or a stable nuclide, and a technique for generating a rare element from an element abundant in nature. And a nuclide conversion method.

[0002]

2. Description of the Related Art Conventionally, a method of converting a small amount of nuclide into a nuclide, such as a heavy element synthesis by a fusion reaction using a heavy ion accelerator, has been used for a large amount of radioactive waste and the like contained in a high-level radioactive waste. As a method for efficiently and effectively converting long-lived radionuclides in a short time, a so-called annihilation process is known. The annihilation treatment includes minor actinides such as NP, Am, and Cm contained in high-level radioactive waste, long-lived fission products such as Tc-99 and I-129, and exothermic Sr-90 and Cs-. 137 and Rh,
After separating useful platinum group elements such as Pd according to the characteristics of each element (group separation), neutrons etc. are irradiated to minor actinides and fission products with long half-lives to generate nuclear reactions Then, it is a nuclide conversion treatment to convert to short-lived or non-radioactive nuclides, while separating and recovering useful elements and long-lived radionuclides contained in high-level radioactive waste and aiming for effective use of useful elements, Convert long-lived radionuclides into short-lived or stable nuclides.

In the annihilation treatment, the actinoids are annihilated by neutron irradiation in a nuclear reactor such as a fast breeder reactor or an actinoid firing furnace, the actinoids are crushed by proton irradiation in an accelerator, and gamma ray irradiation is performed in an accelerator. For example, three types of methods for eliminating cesium, strontium, and the like are known. Neutron irradiation in a nuclear reactor can rationally process minor actinides with a large neutron reaction cross-section, and in particular, direct fission of transuranium elements, which hardly cause fission by irradiation with high-speed neutrons be able to. However, for long-lived fission products which are hardly annihilated by neutron irradiation such as a nuclear reactor, for example, Sr-90 and Cs-137 having a small neutron reaction cross section, annihilation processing using an accelerator is applied.

Unlike the nuclear reactor, the annihilation process using an accelerator can be operated in a subcritical state, and therefore has advantages such as excellent safety related to criticality and a large degree of freedom in design. An accelerator is used. In the annihilation process using the proton accelerator, for example, 500 MeV to 2 Ge
Utilizing a nuclear fragmentation reaction that irradiates high energy protons of about V to crush the target nucleus, the nuclear nucleation reaction is directly used to convert nuclides, and a large number of neutrons generated by the fragmentation of the target nucleus Is injected into a subcritical blanket around the target nucleus to generate a fission reaction, or a neutron capture reaction to generate a nuclide transmutation reaction. Thereby, for example, transuranium elements such as neptunium and americium and long-lived fission products can be extinguished, and the heat generated in the subcritical blanket is recovered to generate electric power, and the electric power required to operate the proton accelerator Can be self-sufficient.

In the annihilation processing using an electron beam accelerator, photonuclear reactions are caused by gamma rays generated by, for example, bremsstrahlung radiation of an electron beam, or gamma rays generated by inverse Compton scattering by combining an electron storage ring and an optical cavity. For example, long-lived fission products such as strontium and cesium and transuranium elements are annihilated by utilizing giant resonance such as (γ, N) reaction and (γ, fission) reaction.

[0006]

However, in the case of performing nuclide conversion using a nuclear reactor or an accelerator as in the annihilation processing according to the above-described prior art, a large-scale and expensive apparatus must be used. There is a problem that the cost required for nuclide conversion increases. In addition, for example, when processing Cs-137, which is a long-lived fission product, it is necessary to convert Cs-137 released from a nuclear power plant of about 1 million KW into another nuclide using an accelerator. The required electric power reaches several millions of kilowatts, and there is a problem that an accelerator having a high intensity and a large current is required and the efficiency is low.

In a nuclear reactor such as a light water reactor, for example, the thermal neutron flux is about 1 × 10 ¹⁴ / cm ² / sec, whereas the neutron flux required for nuclide conversion of Cs-137 having a small neutron reaction cross section is Is 1 × 10 ¹⁷ to 1 × 10 ¹⁸ / cm ² /
sec, and there is a problem that a necessary neutron flux cannot be obtained. The present invention has been made in view of the above circumstances. For example, compared with a large-scale apparatus such as an accelerator or a nuclear reactor, a nuclide conversion apparatus and a nuclide conversion that can perform a nuclide conversion with a relatively small apparatus are provided. The aim is to provide a method.

[0008]

In order to solve the above-mentioned problems and to achieve the above object, a nuclide conversion apparatus according to the present invention according to the present invention comprises a palladium or palladium alloy,
Structures (structure 11, multilayer structure 32, cathode 72, multilayer structure 89, multilayer structure 102 in the embodiment) made of a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy; The storage unit (the storage chamber 31 or the storage container 103 or the electrolytic cell 83 in the embodiment) and the discharge unit (the embodiment) which are arranged so as to sandwich the body from both sides and form a closed space that can be sealed by the structure. Discharge chamber 34 or discharge vessel 101 or vacuum vessel 85).
High pressure means (the deuterium cylinder 35 or the deuterium cylinder 106 or the power supply 81 in the embodiment) for setting the storage part side, which is one surface side of the structure, to a state in which the pressure of deuterium is relatively high. ) And means for lowering the pressure of the deuterium on the discharge portion side, which is the other surface side of the structure, (the turbo molecular pump 38,
110 and rotary pumps 39 and 111 or evacuation pump 91) and a substance for performing nuclide conversion on one surface of the structure ( ¹³³ Cs, ¹² C, ²³ Na in the embodiment).
(In the embodiment, step S04 or step S22 or step S44 or step S04a).

According to the nuclide conversion apparatus having the above-described structure, one surface side and the other surface side of the structure are brought into contact with the substance to be subjected to nuclide conversion on one surface of the structure having a multilayer structure. And a substance that undergoes nuclide conversion with deuterium by generating a deuterium pressure difference between one surface side and the other surface side within the structure by providing a deuterium pressure difference between On the other hand, a nuclide conversion reaction can be generated with good reproducibility.

Furthermore, in the nuclide conversion apparatus according to the present invention, the high-pressure means is a deuterium supply means for supplying deuterium gas to the storage part (the deuterium cylinders 35 and 106 in the embodiment). ), And the pressure reducing means includes an exhaust means (the turbo molecular pumps 38 and 110 and the rotary pumps 39 and 11 in the embodiment) for evacuating the discharge section.
(1) is provided.

According to the nuclide conversion apparatus having the above-described structure, the pressure difference between the deuterium is formed in the structure by pressurizing the occlusion part by the deuterium supply means and depressurizing the discharge part by the exhaust means. be able to.

Further, in the nuclide conversion apparatus according to the present invention, the high-pressure means supplies the storage section with an electrolytic solution containing deuterium (the electrolytic solution 84 in the embodiment). An electrolyzing means (power supply 81 in the embodiment) for electrolyzing the electrolytic solution using the structure as a cathode, and the pressure reducing means is an exhaust means (vacuum in the embodiment) for bringing the discharge section into a vacuum state. An exhaust pump 91) is provided.

[0013] According to the nuclide conversion apparatus having the above structure, the structure is used as a cathode, and the electrolytic solution is electrolyzed on one surface side of the structure so that deuterium can be occluded in the structure with a large effective pressure. Further, a pressure difference of deuterium can be formed in the structure by reducing the pressure of the discharge portion to a vacuum state by the exhaust means.

Further, in the nuclide conversion apparatus according to the present invention, the conversion substance contacting means may include a conversion substance stacking means for stacking the substance to be subjected to the nuclide conversion on one surface of the structure. Or step S04 or step S44 or step S04a).

According to the nuclide conversion apparatus having the above structure, a substance to be subjected to nuclide conversion can be stacked on one surface of the structure by a conversion material stacking means, for example, a film forming process such as electrodeposition, vapor deposition, or sputtering. .

Further, in the nuclide conversion apparatus according to the present invention as set forth in claim 5, the conversion substance contacting means supplies the storage section with the substance to be subjected to the nuclide conversion, so that one surface of the structure is the nuclide. It is characterized in that a conversion substance supply means (step S22 in the embodiment) for exposing to a gas or liquid containing a substance to be converted is provided.

According to the nuclide conversion apparatus having the above-described structure, for example, the substance to be subjected to nuclide conversion is brought into contact with one surface of the structure by mixing the substance to be subjected to nuclide conversion into a gas or liquid containing deuterium. Can be.

Further, in the nuclide conversion apparatus according to the present invention, the structure may be arranged such that the structure is directed from the other surface side to the one surface side, and sequentially stores palladium or a palladium alloy or hydrogen other than palladium. A base material (Pd substrate 23 in the embodiment) made of a metal or a hydrogen storage alloy other than a palladium alloy, and palladium or a palladium alloy formed on the surface of the base material, or a hydrogen storage metal other than palladium or a non-palladium alloy A hydrogen storage alloy,
A mixed layer (mixed layer 22 in the embodiment) made of a material having a low work function (CaO in the embodiment); and palladium or a palladium alloy or a hydrogen storage material other than palladium formed on the surface of the mixed layer. Surface layer made of hydrogen storage alloy other than metal or palladium alloy (P in the embodiment)
d layer 21).

According to the nuclide conversion apparatus having the above structure, the reproducibility of the generation of the nuclide conversion reaction can be improved by providing a mixed layer containing a substance having a low work function in the structure having a multilayer structure.

Further, the nuclide transmutation method of the present invention according to the present invention provides a structure comprising palladium or a palladium alloy, a hydrogen storage metal other than palladium, or a hydrogen storage alloy other than a palladium alloy (in the embodiment). Structure 1
1, the multilayer structure 32, the cathode 72, the multilayer structure 89, and the multilayer structure 102) are subjected to a high pressure treatment (implementation) in which one surface side of the structure has a relatively high deuterium pressure. Step S07 or step S25 or step S46), and a pressure lowering process (step S05 or step S23 in the embodiment) for setting the other surface side of the structure to a relatively low deuterium pressure state. Or step S45) and a conversion substance contacting process of bringing a substance to be subjected to nuclide conversion into contact with one surface of the structure (step S04 or step S22 or step S22 in the embodiment).
44 or step S04a).

According to the nuclide conversion method as described above, one surface side of the structure and the other surface of the structure are brought into contact with each other on one surface of the structure having a multilayer structure. A substance that undergoes nuclide conversion with deuterium by generating a deuterium flux from one surface side to the other surface side within the structure by providing a deuterium pressure difference between the two sides. In contrast, a nuclide conversion reaction can be generated with good reproducibility.

Further, in the nuclide conversion method of the present invention as set forth in claim 8, the conversion material contact treatment is performed by stacking a conversion material lamination process (stacking) on one surface of the structure, the material to be subjected to the nuclide conversion. Or step S04 or step S44 or step S04a) in the form of, or a conversion substance supply process in which one surface of the structure is exposed to a gas or liquid containing the substance to be converted into nuclide (step S22 in the embodiment) ).

According to the above nuclide conversion method, a substance to be subjected to nuclide conversion is stacked on one surface of the structure by a conversion material lamination process, for example, a film formation process such as electrodeposition, vapor deposition, or sputtering. For example, by mixing a substance to be transmuted into a gas or liquid containing deuterium, the substance to be transmuted can be brought into contact with one surface of the structure.

Further, in the nuclide conversion method according to the present invention as set forth in claim 9, the conversion substance contact treatment is characterized in that the substance to be converted is brought into contact with one surface of the structure.

According to the above-described nuclide conversion method, the generation of a nuclide conversion reaction can be promoted by converting a substance to be converted into a nuclide having a similar isotope ratio composition.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining the principle of the nuclide conversion method according to the first embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional configuration diagram illustrating a structure 11 used in the nuclide conversion method according to the first embodiment of the present invention, and FIG. 3 is a configuration diagram of a nuclide conversion device 30 according to the first embodiment of the present invention. FIG. 4 is a cross-sectional configuration diagram showing the multilayer structure 32 in the nuclide conversion apparatus 30 shown in FIG. 3, FIG. 5A is a cross-sectional configuration diagram of the mixed layer 22, and FIG. FIG. 6 is a cross-sectional view of the structure 11 including the mixed layer 22, and FIG.
FIG. 2 is a configuration diagram of an apparatus for adding a substance to be subjected to nuclide conversion to a device.

An apparatus 10 for realizing the nuclide conversion method according to the present embodiment includes, for example, as shown in FIG. 1, palladium (Pd) or an alloy of Pd, or another metal that absorbs hydrogen (for example, Ti) or For example, a substantially plate-shaped structure 11 made of these alloys and the like, and this structure 11
And a substance 14 for radionuclide conversion attached to one surface 11A of the two surfaces of the structure 11,
The 1A side is a region 12 where the pressure of deuterium is high due to, for example, pressurization or electrolysis, and the other surface 11B side is a region 13 where the pressure of deuterium is low due to evacuation or the like. A stream 15 of hydrogen is produced,
This is a device in which nuclide conversion is performed by reacting deuterium with a substance 14 to be nuclide-converted. Here, the structure 1
1, preferably a Pd substrate 2 as shown in FIG.
3, a mixed layer 22 of Pd and a substance having a relatively low work function, that is, a substance that easily emits electrons (for example, a substance having a work function of less than 3 eV) is formed.
Is formed by laminating a Pd layer 21 on the surface of.

As shown in FIG. 3, the nuclide conversion apparatus 30 according to the present embodiment is hermetically sealed through an occlusion chamber 31 whose interior can be kept airtight and a multilayer structure 32 inside the occlusion chamber 31. A discharge chamber 34 provided so as to be able to be held, a deuterium cylinder 35 for supplying deuterium into the storage chamber 31 via a variable leak valve 33, and a discharge chamber vacuum gauge 36 for detecting the degree of vacuum in the discharge chamber 34. For example, by detecting a gaseous reaction product generated from the multilayer structure 32 and measuring the amount of deuterium in the discharge chamber 34, the multilayer structure 32
Analyzer 37 for evaluating the amount of permeation of deuterium permeating through
And a turbo-molecular pump 38 for always keeping the inside of the discharge chamber 34 in a vacuum state, and a rotary pump 39 for roughing the inside of the discharge chamber 34 and the turbo-molecular pump 38.

Further, the nuclide conversion device 30 includes an electrostatic analyzer for detecting photoelectrons, ions, and the like emitted from atoms on the surface of the multilayer structure 32 excited by irradiation with, for example, X-rays, electron beams, or particle beams. 40, and an X-ray (X-ray Photo-electron Spectrometr) that irradiates X-rays on the surfaces of both surfaces of the multilayer structure 32 that are exposed to deuterium in the storage chamber 31.
y: X-ray gun 41 for X-ray irradiation photoelectron spectrum analysis)
A pressure gauge 42 for detecting the pressure in the storage chamber 31 into which deuterium has been introduced, and an X-ray detector including, for example, a high-purity germanium detector 44 having a beryllium window 43,
A storage chamber vacuum gauge 45 for detecting the degree of vacuum in the storage chamber 31;
For example, a vacuum valve 46 for keeping the inside of the storage chamber 31 in a vacuum state before the introduction of deuterium or the like, a turbo molecular pump 47 for making the storage chamber 31 a vacuum state, and roughing the inside of the storage chamber 31 and the turbo molecular pump 47. Rotary pump 48 for
It is comprised including.

Then, the pressure of the deuterium is relatively high in the storage chamber 31 side of the multilayer structure 32, and the multilayer structure 32
The pressure of deuterium is relatively low on the side of the discharge chamber 34 of the multi-layer structure 32, and a pressure difference of deuterium is formed on both surfaces of the multilayer structure 32, so that the flow of deuterium from the storage chamber 31 to the release chamber 34 is changed. To produce Here, for example, as shown in FIG.
In the multilayer structure 32, a mixed layer 22 of a substance having a relatively low work function (for example, a substance having a work function of less than 3 eV) and Pd is formed on the surface of the Pd substrate 23.
A Pd layer 21 is laminated on the surface of
Cesium (Cs) as a substance that performs nuclide conversion on the surface of
A layer 52 is added.

The nuclide conversion device 30 according to the present embodiment has the above-described configuration. Next, a method of performing nuclide conversion using the nuclide conversion device 30 will be described with reference to the accompanying drawings.

First, for example, a Pd substrate 23 (for example, 25 mm long × 25 mm wide × 0.1 mm thick, purity of 99.5% or more) shown in FIG. 2 is ultrasonically cleaned in acetone for a predetermined time. Degreasing. Then, in a vacuum (for example, 1.33 × 10 ⁻⁵ Pa or less), for example, 90
Annealing, that is, heat treatment is performed at a temperature of 0 ° C. for a predetermined time (for example, 10 hours) (Step S01). Next, for example, the Pd substrate 23 annealed at room temperature is subjected to etching treatment with heavy aqua regia for a predetermined time (for example, 100 seconds) to remove impurities on the surface (step S0).
2).

Next, sputtering using an argon ion beam is performed.
On the Pd substrate 23 after the etching process by using the
The structure 11 is formed by performing a film forming process. Here, for example
For example, the thickness of the Pd layer 21 shown in FIG.^-Tenm and
However, the mixed layer 22 of a material having a low work function and Pd is, for example,
For example, as shown in FIG.
^-Tenm CaO layer 57 and, for example, 100.10^-Tenm
And the Pd layers 56 are alternately laminated.
The thickness of 2 is 1000.10^-Tenm. And mixing
On the surface of the layer 22, a Pd layer 21^-Tenm
By forming a film, the structure 11 was formed (step S
03).

Next, a D ₂ O dilute solution of CsNO ₃ (CsN
As a substance to be subjected to nuclide conversion by electrolysis of an O ₃ / D ₂ O solution, for example, Cs is added to the surface of the structure 11 on which the film is formed. For example, as shown in FIG.
Using a mM CsNO ₃ / D ₂ O solution as an electrolyte 62, a platinum anode 63 was connected to the anode of a power supply 61, and the structure 11 was used as a cathode.
Is connected, and electrolysis is performed at a voltage of, for example, 1 V for 10 seconds to cause a reaction represented by the following chemical formula (1) on the surface of the structure 11 to add the Cs layer 52 to the multilayer structure. 32 are formed (step S04).

[0035]

Embedded image

Then, with the Cs layer 52 of the multilayer structure 32 facing the storage chamber 31 side, the storage chamber 31 and the release chamber 34 are closed in an airtight state with the multilayer structure 32 interposed therebetween.
First, the discharge chamber 34 is evacuated by the rotary pump 39 and the turbo molecular pump 38. Then, the variable leak valve 33 is closed, the vacuum valve 46 is opened, and the storage chamber 31 is evacuated by the rotary pump 48 and the turbo molecular pump 47 (step S05). next,
After the degree of vacuum in the storage chamber 31 is sufficiently stabilized (for example, 1 × 1
To 0 ^-5 Pa or less states), to analyze the elements present on the surface of the storage chamber 31 side of the multilayer structure 32 by XPS (step S06). That is, the surface of the multilayer structure 32 is irradiated with X-rays from the X-ray gun 41, and the energy of photoelectrons emitted from the atoms on the surface of the multilayer structure 32 excited by the X-ray irradiation is electrostatically reduced. It is detected by the analyzer 40. Thereby, the element existing on the surface of the multilayer structure 32 on the storage chamber 31 side is identified.

Next, after heating the multilayer structure 32 at a temperature of, for example, 70 ° C. by a heating device (not shown), the vacuum valve 46 is closed to stop the evacuation of the storage chamber 31, and the variable leak valve 33 is opened. Is opened and deuterium gas is introduced into the storage chamber 31 at a predetermined gas pressure to start a nuclide conversion experiment. Here, the predetermined gas pressure when introducing the deuterium gas is, for example, 1.01325 × 10 ⁵ Pa (so-called 1
Atm). Then, a gaseous reaction product (for example, mass number A = 1 to 140) is obtained by the mass analyzer 37 in the discharge chamber 34.
Is measured, and the diffusion behavior of deuterium that has been transmitted through the multilayer structure 32 and released into the release chamber 34 is evaluated. Further, X-rays are measured by the high-purity germanium detector 44 on the storage chamber 31 side of the multilayer structure 32 (step S07). The amount of deuterium released through the multilayer structure 32 into the discharge chamber 34 is, for example, the degree of vacuum in the discharge chamber 34 detected by the discharge chamber vacuum gauge 36 and the exhaust speed of the turbo molecular pump 38. Calculated based on

A predetermined time, for example, several tens of hours after the introduction of the deuterium gas into the storage chamber 31 is started, the multilayer structure 32
To room temperature. Then, the variable leak valve 33 is closed to stop the introduction of deuterium gas into the storage chamber 31, and the vacuum valve 46 is further opened to evacuate the storage chamber 31 to end the nuclide conversion experiment. After the degree of vacuum in the storage chamber 31 is sufficiently stabilized (for example, 1 × 10 ^−5).
In a state (Pa or less), elements existing on the surface of the multilayer structure 32 on the storage chamber 31 side are analyzed by XPS to measure products (Step S08).

Then, the processing of the above-described steps S06 to S07 is repeated to measure a time change of the nuclide conversion reaction (step S09). And the multilayer structure 3
2 is taken out from the nuclide conversion device 30, and the nuclide conversion experiment is terminated (step S10).

The following are two experimental results of the nuclide conversion experiment performed by the above-described nuclide conversion method according to the present embodiment,
That is, Examples 1 and 2 when the same experiment is performed twice will be described with reference to FIGS. 7 and 8.
FIG. 7 is a graph showing the relationship between X and X on the surface of the multilayer structure 32 shown in FIG.
FIG. 8 is a graph showing the spectrum of Pr by PS, and FIG. 8 is a graph showing the time change of the number of atoms of Cs and Pr on the surface of the multilayer structure 32 shown in FIG. According to the results of XPS analysis in Example 1 and Example 2, in Examples 1 and 2, Cs (atomic number Z = 55) of the multilayer structure 32 decreases as time passes. As shown in the Pr spectrum by XPS shown in FIG.
r (praseodymium, atomic number Z = 59) increased.
Hereinafter, a method for calculating the number of atoms of each element from the spectra for Cs and Pr by XPS will be described.

The intensity of the X-rays emitted from the X-ray gun 41 to the multilayer structure 32 during the XPS measurement is always constant, and the region irradiated with these X-rays is the same as in the first embodiment.
And the same in each measurement of Example 2.
Further, the region irradiated with X-rays on the surface of the multilayer structure 32 is, for example, a circular region having a diameter of 5 mm. From the estimation of the escape depth of emitted photoelectrons, the depth that can be analyzed by XPS is, for example, It was 20 · 10 ⁻¹⁰ m. Also, Pd
Since Pd constituting the substrate 23 is an fcc (face-centered cubic lattice) crystal, the number of Pd atoms was calculated to be 3.0 × 10 ¹⁵ from the peak intensity of the Pd spectrum obtained by XPS.

The peak intensity of the spectrum of each element obtained by XPS and the spectrum of Pd are obtained by referring to the ionization cross-sectional area of each element, that is, the ratio of the core electrons of the element absorbing and exciting, for example, X-rays. The number of atoms of each element is calculated by comparing the peak intensity with the peak intensity of each element. Table 1 shows calculated values of the ionization cross section of each element.
Is shown as a relative value when the value (2.22 × 10 ⁻²⁴ m ² ) for the 1s orbit is “1”. In Table 1 below, 2p of Si, 2p of S, and 2p of Cl were calculated as the sum of 2p3 _{/ 2} and 2p1 _{/ 2} .

[0043]

[Table 1]

As shown in FIG. 8, in Example 1, 1.3 × 10 ¹⁴ Cs in the initial state were reduced to 8 × 10 ¹³ after 48 hours, and 5 × after 120 hours. × 10
^It has been reduced to ¹³ . On the other hand, 3 × 10 ¹³ Pr that did not exist before the start of the experiment was detected 48 hours later, and 1
After 20 hours, the number increased to 7 × 10 ¹³ . Similarly, in Example 2, a decrease in the number of Cs atoms, generation of Pr, and an increase in the number of Pr atoms were observed over time from the start of the experiment. Is shown. Thus, it can be interpreted that nuclide conversion from Cs to Pr has occurred.

In the following, it will be considered whether or not the detected Pr is derived from impurities. In Example 1 and Example 2 according to the above-described embodiment, the elemental analysis is performed without taking out the multilayer structure 32 from the vacuum container including the occlusion chamber 31 and the release chamber 34.
It is considered that the impurities are mixed due to impurities contained in the deuterium gas (D ₂ gas) and impurities inside the multilayer structure 32. The D ₂ gas has, for example, a purity of 99.6%. As impurities, N ₂ and D ₂₀ are 10 ppm or less, and O _2, CO ₂ and CO are 5 ppm or less. _{When the two} gases were analyzed, no gas other than these impurities and hydrocarbons was detected.

On the other hand, in the multilayer structure 32, the purity of Pd is 99.5%, and the purity of CaO and CsNO ₃ is 9%.
9.9%. Glow discharge mass spectrometry (GD-
As a result of performing quantitative analysis of lanthanoids ( ₅₇ La to ₇₁ Lu) on the multilayer structure 32 before the start of the experiment by MS), 0.02 ppm of Nd was detected, and other lanthanoids other than Nd were below the detection limit, that is, It was 0.01 ppm or less. Here, the multilayer structure 32 used in Example 1 and Example 2 (for example, 0.7 g ≒ 7 × 10 ⁻³ mol)
Assuming that 0.01 ppm of Pr, which is the detection limit, is present in the multilayer structure, there will be 4.2 × 10 ¹³ Pr atoms in the multilayer structure 32.

In this case, the Pr atoms detected in Examples 1 and 2 are less than the detection limit based on the above assumption.
Assuming that it is due to r atoms, all Pr atoms below these detection limits are several tens of
It is necessary to assume that the atoms are arranged so as to be concentrated in a region having a depth of 10 ⁻¹⁰ m, and Pr atoms dispersed and arranged as impurities in the multilayer structure 32 are formed on the surface of the multilayer structure 32. Physical phenomena that are concentrated only in the vicinity are not thermodynamically possible, and Pr atoms detected in the first and second embodiments are considered to be impurities contained in the multilayer structure 32 in advance. I cannot conclude. In addition, it can be determined that if the impurity is contained in the multilayer structure 32 in advance, a change in the number of atoms with time is not observed and a constant value is maintained. From the above, the P detected in Example 1 and Example 2
It can be concluded that r was produced as a result of the transmutation reaction.

The experimental results in the above-described Examples 1 and 2 are, for example, Fu values published by the Atomic Energy Society of America.
sion Technology (Y. Iwamura, T. Itoh, N. Gotoh
andI. Toyoda, "Detection of Anomalous Elements, X-
ray and Excess Heat in aD2-Pd System and its Inter
pretation by the Electron-Induced Nuclear Reaction
Model ", Fusion Technology, vol.33, No.4, P.476,19
This can be explained very well by the EINR model published in 98). According to the EINR model, Pr is considered to be generated from Cs by the following equations (1) and (2). In the following chemical formulas (2) and (3),
d is deuterium, e is an electron, ² n is a dineutron, and ν is a neutrino.

[0049]

Embedded image

[0050]

Embedded image

As shown in the chemical formula (2), the EINR model considers that deuterium captures an electron to generate a dineutron, and at the same time reacts with a substance such as Cs to cause nuclide conversion. Note that β decay in chemical formula (3), that is,
Β ⁻ from ¹⁴¹ Cs (= ¹³³ Cs + 4 ² n) to ¹⁴¹ Pr
The collapse symbol is omitted.

As described above, the nuclide according to the present embodiment
According to the conversion device 10, for example, relative to a nuclear reactor, an accelerator, etc.
A relatively small configuration without the need for large equipment
The process of nuclide conversion can be performed in the process. In addition, this implementation
According to the nuclide conversion method in the form of
Not detected, but increased after the start of the nuclide conversion experiment
The number of atoms of Pr _TwoGas and multilayer structure 3
2 may have been detected due to impurities previously contained in
And the nuclide conversion reaction from Cs to Pr occurs
Can be shown with good reproducibility.

In the above-described embodiment,
The cesium (Cs) layer 52 is added to the surface of the Pd layer 21 as a substance to be subjected to nuclide conversion to form the multilayer structure 32. However, the present invention is not limited to this.
Alternatively, other substances such as carbon (C) may be added. Hereinafter, as a first modified example of the present embodiment,
The case where, for example, carbon (C) is added as a substance for performing nuclide conversion on the surface of the Pd layer 21 will be described with reference to FIGS. FIG. 9 is a graph showing the time change of the number of atoms of C, Mg, Si and S on the surface of the multilayer structure 32 in Example 3, and FIG. It is a graph showing the time change of each number of atoms of C and Mg and Si and S on the surface of No. 32.

In the first modified example, a point that is significantly different from the above-described first embodiment is a method of forming the multilayer structure 32, particularly, the processing in the above-described step S04.
That is, after the above-described step S03, the Pd substrate 2
By exposing the structure 11 composed of the Pd layer 3 and the mixed layer 22 and the Pd layer 21 to the atmosphere, carbon (C) in the atmosphere is attached to the surface of the Pd layer 21 to form the multilayer structure 32 (step S14). ). Then, the Pd layer 21 to which C is attached faces the storage chamber 31 side, the storage chamber 31 and the release chamber 34 are closed with the multilayer structure 32 interposed, and both the storage chamber 31 and the release chamber 34 are respectively closed. Evacuate (Step S1)
5). Then, the processing from step S06 is performed.

Hereinafter, two experimental results of the nuclide conversion experiments performed by the nuclide conversion method according to the first modification of this embodiment, that is, Examples 3 and 4 when the same experiment is performed twice. Will be described with reference to the accompanying drawings. In this case, according to the results of the XPS analysis in Examples 3 and 4, the multilayer structure 3 was used in Examples 3 and 4.
The C of No. 2 decreased with time, and Si and S as reaction products and Mg as an intermediate product were detected. Then, similarly to the above-described embodiment, X
From the spectra of C and Mg and Si and S by PS, the number of atoms of each element was calculated.

As shown in FIG. 9, in Example 3, the number of C atoms derived from hydrocarbons decreased 44 hours after the start of the experiment, but did not exist before the start of the experiment. Mg was detected after 44 hours, and slightly decreased after 116 hours. Furthermore, Si and S, which did not exist before the start of the experiment, increased monotonically after 44 hours and 116 hours.

As shown in FIG. 10, in Example 4, the number of C atoms derived from hydrocarbons decreased monotonically at 24 hours, 76 hours, and 116 hours after the start of the experiment. 2 Mg that did not exist before the start of the experiment
It forms after 4 hours and monotonically decreases after 76 hours and 116 hours. Furthermore, Si and S, which did not exist before the start of the experiment, increased monotonically after 24 hours, 76 hours, and 116 hours.

From the above results, C is converted into a nuclide by the nuclide conversion method according to the first modification of the present embodiment, and Mg
And Si and S are generated. in this case,
According to the above-mentioned EINR model, nuclide conversion of C is represented by the above chemical formula (2) and the following chemical formula (4). In the formula (4) was reacted by die neutron clusters ^{(6 2 n, 2 2 n} ).

[0059]

Embedded image

Hereinafter, as a second modified example of this embodiment,
FIG. 11 shows a case where, for example, strontium (Sr) is added as a substance for performing nuclide conversion on the surface of the Pd layer 21.
This will be described with reference to FIG. FIG. 11 is a cross-sectional configuration diagram illustrating a multilayer structure 32 according to a second modification of the present embodiment. FIG. 12 is a graph illustrating a spectrum of Mo by XPS on the surface of the multilayer structure 32 illustrated in FIG. FIG. 13 and FIG. 14 are graphs showing the time change of the number of atoms of Sr and Mo on the surface of the multilayer structure 32 shown in FIG. FIG. 15 is a graph showing the isotope abundance ratio of naturally occurring Mo along with the change in the mass number, and FIG. 16 is the Mo isotope existence ratio observed on the surface of the multilayer structure 32 in the fifth embodiment. FIG. 17 is a graph showing the ratio with the change in mass number, and FIG. 17 is a graph showing the isotope abundance ratio of naturally occurring Sr added as a substance to be subjected to nuclide conversion with the change in mass number.

In the second modification, the Sr layer 53 is added to the multilayer structure 32 of the first embodiment described above, instead of the Cs layer 52 made of a substance to be converted into a nuclide. That is, a point that is greatly different from the above-described first embodiment is the method of forming the multilayer structure 32, particularly, the processing in the above-described step S04. In this second modification, P
As the d-substrate 23, for example, length 25 mm × width 25 mm ×
The thickness was 0.1 mm and the purity was 99.9% or more. In the second modification, after the above-described step S03, SrO
For example, Sr is added to the film-forming surface of the structure 11 as a substance to be subjected to nuclide conversion by electrolysis of a D ₂ O dilute solution (Sr (OD) ₂ / D ₂ O solution). For example, in the electrodeposition apparatus 60 shown in FIG. 6, 1 mM Sr (OD) ₂ /
Using the D ₂ O solution as the electrolytic solution 62, the platinum anode 63 is connected to the anode of the power supply 61, the structure 11 is connected to the cathode, and electrolysis is performed at a voltage of, for example, 1 V for 10 seconds. A reaction represented by the following chemical formula (5) is generated on the surface of the substrate and the Sr layer 53 is added to form the multilayer structure 32 (Step S04a).

[0062]

Embedded image

Then, the process from step S05 described above is performed with the Sr layer 53 of the multilayer structure 32 facing the storage chamber 31 side.

Hereinafter, two experimental results of the nuclide conversion experiments performed by the nuclide conversion method according to the second modification of the present embodiment, that is, Examples 5 and 6 when the same experiment was performed twice. Will be described with reference to the accompanying drawings. According to the results of the XPS analysis in the fifth and sixth examples, the Sr of the multilayer structure 32 in the fifth and sixth examples was determined.
(Atomic number Z = 38) decreased with time, and Mo (molybdenum, atomic number Z = 42) increased, for example, as in the spectrum of Mo by XPS shown in FIG.

Here, Sr and M obtained by XPS
When calculating the number of atoms of each element from the spectrum for o, the same method as in the above-described first embodiment was used. In other words, the intensity of the X-rays emitted from the X-ray gun 41 to the multilayer structure 32 at the time of measurement by the XPS is always constant, and the regions irradiated with these X-rays are the same as those of the fifth and sixth embodiments. It was assumed to be the same for each measurement. Further, the region irradiated with X-rays on the surface of the multilayer structure 32 is, for example, a circular region having a diameter of 5 mm. From the estimation of the escape depth of emitted photoelectrons, the depth that can be analyzed by XPS is, for example, It was 20 · 10 ⁻¹⁰ m. Since Pd constituting the Pd substrate 23 is an fcc (face-centered cubic lattice) crystal, the number of Pd atoms was calculated to be 3.0 × 10 ¹⁵ from the peak intensity of the Pd spectrum obtained by XPS.

The peak intensity of the spectrum of each element obtained by XPS and the spectrum of Pd are obtained by referring to the ionization cross-sectional area of each element, that is, the ratio of the core electrons of the element absorbing and exciting, for example, X-rays. The number of atoms of each element was calculated by comparing the peak intensity with the peak intensity of each element.

As shown in FIG. 13, in the fifth embodiment, the initial
1.2 × 10 in state¹⁴Sr that existed for 80 hours
Later 1.0 × 10¹⁴And after 240 hours 8
× 10¹³To 4 × 10 after 400 hours¹³Individually
is decreasing. On the other hand, it did not exist before the experiment started
Mo is about 2.2 × 10 after 80 hours ¹³Detected, 2
About 3.2 × 10 after 40 hours¹³Increased to 400 hours
3.8 × 10 after¹³Is observed to increase
Was. Similarly, in the sixth embodiment shown in FIG.
As the time elapses from the start of the experiment, the number of Sr atoms decreases
And generation of Mo and M which did not exist before the start of the experiment.
An increase in the number of atoms of o was observed, and the slope was almost the same as in Example 5.
Direction. In addition, both of Example 5 and Example 6
In time, the time change of the decrease in the number of Sr atoms and the Mo
The generation and increase in the number of offspring are almost
Therefore, nuclide conversion from Sr to Mo is occurring.
Can be interpreted. Moreover, in both the fifth embodiment and the sixth embodiment,
, Qualitatively good reproducible experimental results are obtained
It can be concluded.

Further, in Example 5, after the end of the nuclide conversion experiment, that is, after the above-described step S10, the surface of the multilayer structure 32 was subjected to secondary ion mass spectrometry (SIMS:
Secondary Ion Mass Spectroscopy)
The isotope abundance ratio of the generated Mo was calculated. For example, FIG.
Compared to the natural isotope abundance ratio of Mo shown in 5,
For example, in the Mo isotope abundance ratio observed in the fifth embodiment shown in FIG. 16, it can be seen that only a specific isotope, ie, ⁹⁶ Mo, protrudes and shows a high abundance. Here, as shown in FIG. 17, for example, in the isotope abundance ratio of naturally occurring Sr added to the multilayer structure 32 as a substance to be subjected to nuclide conversion, only a specific isotope, that is, ⁸⁸ Sr is prominently high. It turns out that it shows the existence rate. That is, the isotope abundance ratio of the substance (Sr) to be subjected to nuclide conversion,
It can be concluded that there is a strong correlation between the isotope abundance ratio of the substance (Mo) that was not present before the start of the experiment and that was generated after the end of the experiment, and was detected in Examples 5 and 6. It can be concluded that the obtained Mo was generated by the transmutation of Sr.

Further, the experimental results in Example 5 and Example 6 can be explained very well by, for example, the above-mentioned EINR model. For example, ⁹⁶ Mo is represented by the above chemical formula (2) and the following chemical formula (6). Probably generated. Note that β decay in chemical formula (6), that is, ⁹⁶ Sr
The sign of β ^- decay from (= ⁸⁸ Sr + 4 ² n) to ⁹⁶ Mo is omitted.

[0070]

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Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a second embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 18 is a diagram illustrating the principle of the nuclide conversion method according to the second embodiment of the present invention, and FIG. 19 is a configuration diagram of a nuclide conversion device 80 according to the second embodiment of the present invention.

An apparatus 70 for realizing the nuclide conversion method according to the present embodiment, for example, as shown in FIG. 18, stores an anode 71 made of, for example, platinum, and an alloy of palladium (Pd) or Pd, or other hydrogen. Metal (eg, T
i) or a cathode 72 made of this alloy or the like, and an anode 71
And a heavy aqueous solution 73 immersed in one surface of the cathode 72; an electrolytic cell 74 which is liquid-tight by the cathode 72; Vacuum container 75 and the cathode 7
The one surface 72A side of the second is a region where the pressure of deuterium is high due to, for example, electrolysis, and the other surface 72B side is a region where the pressure of deuterium is low due to, for example, evacuation. Is produced by reacting deuterium with a substance to be transmuted. Here, the cathode 72 has, for example, a structure similar to that of the structure 11 shown in FIG. 2, and is preferably a substance having a relatively low work function, that is, a substance that easily emits electrons, on the surface of the Pd substrate 23. (For example, a substance having a work function of less than 3 eV) and a mixed layer 22 of Pd are formed,
On the surface of the mixed layer 22, the Pd layer 21 is formed by being laminated.

As shown in FIG. 19, a nuclide conversion apparatus 80 according to the present embodiment includes a power supply 81, an electrolytic cell 83 having a pressure gauge 82, an electrolytic solution 84 stored in the electrolytic cell 83, a vacuum Container 85 and electrolytic solution 8 in electrolytic cell 83
4, a spiral cooling pipe 86 made of, for example, an insulating resin or the like, a catalyst 87, an anode electrode 88 of platinum or the like connected to the cathode of a power supply 81 and immersed in an electrolytic solution 84, and an electrolytic cell 83. The inside is kept liquid-tight, the inside of the vacuum vessel 85 is kept air-tight, and the multi-layered structure 89 connected to the cathode of the power supply 81, the electrolytic cell 83 and the vacuum vessel 85 are stored and controlled at a constant temperature. The apparatus includes a tank 90 and a vacuum pump 91 for evacuating the vacuum vessel 85.

Here, an electrolytic cell 83 made of, for example, an insulating resin or the like and a vacuum vessel 8 made of, for example, stainless steel or the like.
5 are, for example, Kalrez O having excellent chemical resistance.
It is sealed in a liquid-tight and air-tight state by a multilayer structure 89 via a ring or the like, and is connected via the multilayer structure 89 so to speak. The electrolytic solution 84 stored in the electrolytic cell 83 is a heavy aqueous solution containing, for example, cesium (Cs) as a substance to be converted into nuclides, for example, having a concentration of 3.1.
It is a mol / l Cs ₂ (SO ₄ ) heavy aqueous solution. The catalyst 87 is formed by electroplating platinum black on platinum, generates water from most of the hydrogen and oxygen generated by the electrolysis of the electrolytic solution 84, and again forms the electrolytic solution 84.
Return to

The nuclide conversion device 80 according to the present embodiment has the above-described configuration. Next, a method of performing nuclide conversion using the nuclide conversion device 80 will be described with reference to the accompanying drawings.

First, the structure 11 is created in the same manner as in steps S01 to S03 in the nuclide conversion method according to the first embodiment. And this structure 1
1 as a multilayer structure 89, the Pd of this multilayer structure 89
With the layer 21 facing the electrolytic cell 83 side, the electrolytic cell 83 and the vacuum vessel 85 are sealed in a liquid-tight and air-tight state, respectively (step S21). Next, the electrolytic solution 84 is placed in the electrolytic cell 83.
As an example, Cs ₂ (S
O ₄ ) Inject heavy water solution. Further, the space inside the electrolytic cell 83 that is not filled with the electrolytic solution 84 is replaced with nitrogen gas and sealed, and the pressure in the electrolytic cell 83 is reduced to, for example, 1.5 k.
g / cm ² (step S22).

Then, a vacuum pump 91 is
Is exhausted and kept in a vacuum state (step S23).
Then, a coolant is supplied into the cooling pipe 86 made of, for example, an insulating resin or the like, and the temperature inside the electrolytic cell 83 is maintained at a predetermined constant temperature (step S24). And the electrolytic cell 8
An anode electrode 88 made of, for example, platinum immersed in an electrolytic solution 84 and a multilayer structure 89 serving as a cathode are supplied to a power source 8.
1 to generate an electrolysis reaction by the electric power supplied from the power supply 81 (step S25). Here, the current supplied during the electrolysis is, for example, 1 A gradually over 3 hours.
To 2A, and then hold 2A.

Then, 12 hours after the start of the electrolysis, the temperature of the thermostat 90 is set to 70 ° C., and thereafter, this temperature is maintained (step S 26). After the electrolysis is continued for a predetermined time, for example, 7 days, the electrolysis is stopped and the thermostat 9
The temperature of 0 is set to normal temperature (step S27). Then, the multilayer structure 89 is removed from the nuclide conversion device 80, and the surface of the multilayer structure 89 is subjected to secondary ion mass spectrometry (SIMS: Se
Analysis is performed by condary ion mass spectroscopy (step S28).

The results of the nuclide conversion experiment performed by the above-described nuclide conversion method according to the present embodiment, that is, Example 7, will be described below with reference to FIGS. 20 and 21. 20 is a diagram showing the surface of the multilayer structure 89 on the side of the electrolytic cell 83 after the experiment using the nuclide conversion device 80 shown in FIG. 19, and FIG. 21 is a diagram showing the nuclide conversion device 8 shown in FIG.
FIG. 10 is a graph showing the results of SIMS analysis of the surface of the multilayer structure 89 after the experiment using No. 0.

A portion 96 shown in FIG.
If, with respect to a portion 95 of deuterium shown in FIG. 20 is not transmitted, as shown in FIG. 21, the intensity of the secondary ions are coincident for ¹⁴⁰ Ce, ¹³⁹ In La and ¹⁴¹ Pr heavy The intensity of the secondary ion is higher in the portion 96 through which hydrogen has passed, that is, in the portion where the nuclide conversion reaction has occurred. For mass number A = 142, ¹⁴² C
Although it is not possible to determine which of e and ¹⁴² Nd it is, the intensity of the secondary ions is higher in the portion 96 through which deuterium has passed. This allows at least
^It can be concluded that ¹⁴¹ Pr is a substance produced by transmutation of Cs.

As described above, according to the nuclide conversion apparatus 80 of the present embodiment, the nuclide conversion is performed in a relatively small configuration without requiring a relatively large-scale apparatus such as a nuclear reactor and an accelerator. Conversion processing can be performed. Moreover, it is possible to obtain experimental results indicating that a nuclide conversion reaction from Cs to Pr has occurred, despite having a configuration different from that of the nuclide conversion apparatus 30 according to the first embodiment described above. It can show the effectiveness of essential measures. Further, according to the nuclide conversion method according to the present embodiment, the multilayer structure 8
The comparison between the portion 96 through which deuterium has permeated in 9 and the portion 95 through which deuterium has not permeated can reliably show that at least a nuclide conversion reaction from Cs to Pr has occurred.

In this embodiment, a heavy aqueous solution containing a substance to be subjected to nuclide conversion is used as the electrolytic solution 84. However, the present invention is not limited to this. For example, a vacuum is applied on one surface of the multilayer structure 89. A substance to be subjected to nuclide conversion, for example, Cs, is deposited by a deposition process such as vapor deposition or sputtering, and the surface on which the Cs is deposited is directed toward the inside of the electrolytic cell 83.
Electrolytic solution 8 composed of heavy aqueous solution stored in electrolytic cell 83
4 may be soaked. In this case, the heavy aqueous solution does not need to contain a substance to be subjected to nuclide conversion, that is, Cs.

In the present embodiment described above,
Although a heavy aqueous solution containing Cs was used as the electrolytic solution 84, the present invention is not limited to this.
Alternatively, other substances such as sodium (Na) may be added. Hereinafter, as a modification of the present embodiment, for example, sodium (N
The case where a) is added to the heavy aqueous solution will be described.

In this modified example, a point that is significantly different from the above-described second embodiment is the above-described processing from step S22. That is, after the above-described step S21, as the electrolytic solution 84 in the electrolytic cell 83, for example, only 400 ppm of sodium is added, and the concentration is 4.3 m.
ol / l of LiOD heavy water solution is injected. Further, the space inside the electrolytic cell 83 that is not filled with the electrolytic solution 84 is replaced with nitrogen gas and sealed, and the pressure inside the electrolytic cell 83 is maintained at, for example, 1.5 kg / cm ² (step S3).
2).

Then, a vacuum pump 91 is
Is exhausted and kept in a vacuum state (step S33).
Then, a coolant is supplied into the cooling pipe 86 made of, for example, an insulating resin or the like, and the temperature inside the electrolytic cell 83 is maintained at a predetermined constant temperature (step S34). And the electrolytic cell 8
An anode electrode 88 made of, for example, platinum immersed in an electrolytic solution 84 and a multilayer structure 89 serving as a cathode are supplied to a power source 8.
1 to generate an electrolysis reaction by the electric power supplied from the power supply 81 (step S35). Here, the electric current supplied at the time of electrolysis is gradually reduced to, for example, 6 hours.
Increase from 5A to 2A, then hold 2A.

After the electrolysis is continued for a predetermined time, for example, 7 days, the electrolysis is stopped, and the temperature of the thermostat 90 is set to normal temperature (step S36). Then, the multilayer structure 89 is removed from the nuclide conversion device 80, and the surface of the multilayer structure 89 is analyzed by an electron probe micro analyzer (EPMA: Electron Probe Microanalysis) (step S37).

Hereinafter, the results of three nuclide conversion experiments performed by the nuclide conversion method according to the modification of the above-described second embodiment of the present invention, that is, an example in which the same experiment was performed three times, will be described. Eighth and ninth and tenth embodiments will be described. Table 2 below shows that the inductively coupled plasma-Auger electron spectrum analysis (ICP-AES: Inductive Coupler)
The analysis results of the electrolytic solution 84 by d Plasma-Auger Electron Spectrometry are shown. The analysis result of the electrolytic solution 84 before the start of the experiment was used as a comparative example.

[0088]

[Table 2]

As shown in Table 2, the electrolytic solution 84 before the start of the experiment contains 430 ppm of Na and 1 ppm or less of Al, which is below the detection limit. On the other hand, after the nuclide conversion experiment, N
The value of a was several tens ppm, which is about one digit lower, and the content of Al was several hundred ppm. The change of the electrolytic solution 84 before and after the start of the experiment is only to apply an electric current from the power supply 81 to perform the electrolysis, and no other substance is added from the outside. Further, in terms of the number of atoms (Atom in Table 2), the decreased Na
Is about 2.2 × 10 ²¹ to 2.0 × 10 ²¹ , and it can be confirmed that the number of atoms almost coincides with the increase in Al.

The result is represented by the above chemical formula (2) and the following chemical formula (7) in the above-mentioned EINR model.

[0091]

Embedded image

Here, Na has a natural abundance of ²³ Na of 10%.
0%, and Al has a natural abundance of ²⁷ Al of 100%. From the conventional experimental data, it can be inductively determined that nuclide conversion is likely to occur between nuclides with similar isotopic composition,
The high possibility that Na is converted to Al is that Na, Al
It can also be inferred from the fact that only one stable isotope exists for both elements. In addition, the surface of the multilayer structure 89 is EPM
As a result of the analysis by A, Al was also detected from the center of the multilayer structure 89, that is, the portion through which deuterium permeated.
Since Al is an amphoteric metal, it can be dissolved in the electrolytic solution 84. However, since Al is also detected from the central surface of the multilayer structure 89, it is concluded that Na was converted to nuclide and Al was generated. can do.

In this embodiment, a heavy aqueous solution containing a substance to be subjected to nuclide conversion is used as the electrolytic solution 84. However, the present invention is not limited to this. For example, a vacuum is applied on one surface of the multilayer structure 89. A substance that undergoes nuclide conversion, for example, Na, is deposited by deposition or a film formation process of a sputtering method, and the surface on which the Na is deposited is directed toward the inside of the electrolytic cell 83.
Electrolytic solution 8 composed of heavy aqueous solution stored in electrolytic cell 83
4 may be soaked. In this case, the heavy aqueous solution does not need to contain a substance to be subjected to nuclide conversion, that is, Na.

Hereinafter, a nuclide conversion apparatus and a nuclide conversion method according to a third embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 22 is a configuration diagram of the nuclide conversion device 100 according to the third embodiment of the present invention.

The nuclide conversion apparatus 100 according to the present embodiment
Is provided via a discharge container 101 whose inside can be kept airtight, a storage container 103 provided inside the discharge container 101 so as to be able to hold airtight through a multilayer structure 102, and a regulator valve 104 and a valve 105. A deuterium cylinder 106 for supplying deuterium into the storage container 103, a pressure gauge 107 for detecting the pressure in the storage container 103, and the discharge container 101 and the storage container 10 via a vacuum valve 108.
3, a turbo-molecular pump 110 for keeping the inside of the discharge vessel 101 in a vacuum state, a turbo-molecular pump 1 for keeping the inside of the discharge vessel 101 and the storage vessel 103, and the turbo-molecular pump 1
A rotary pump 111 for roughing the inside of 10;
A vacuum gauge 112 for detecting the degree of vacuum in the discharge container 101 is provided.

The nuclide conversion apparatus 100 according to the present embodiment has the above-described configuration.
A method of performing nuclide conversion using will be described with reference to the accompanying drawings.

First, for example, a Pd substrate 23 shown in FIG. 2 (for example, a diameter of 70 mm × a thickness of 0.1 mm, a purity of 99.9%
Is degreased by ultrasonic cleaning in acetone for a predetermined time. Then, annealing or heat treatment is performed at a temperature of, for example, 900 ° C. for a predetermined time (for example, 10 hours) in an Ar gas atmosphere (step S41). Next, for the Pd substrate 23 after annealing,
For example, an impurity is removed from the surface by performing an etching process with aqua regia diluted 1.5 times at room temperature for a predetermined time (for example, 100 seconds) (step S42).

Next, in the same manner as in step S03, a film is formed on the etched Pd substrate 23 by sputtering using an argon ion beam to form the structure 11 (step S43). . Then, as in step S04 described above, CsNO ₃
The Cs layer as a substance to be subjected to nuclide conversion by electrolysis of a D ₂ O dilute solution (CsNO ₃ / D ₂ O solution) of the structure 11
To form a multilayer structure 102 (step S44).

Then, with the Cs layer of the multilayer structure 102 facing the storage container 103 side, the storage container 103 and the discharge container 101 are closed in an airtight manner with the multilayer structure 102 interposed therebetween. Then, first, the valve 105 is closed, the vacuum valve 108 of the connection pipe 109 is opened, and the discharge container 10 is opened.
1 and the storage container 103 are evacuated by the rotary pump 111 and the turbo molecular pump 110 (step S45).

Next, the multilayer structure 102 is heated by a heating device (FIG.
After heating to a temperature of, for example, 70 ° C.
The valve 108 is closed and the evacuation of the storage container 103 is stopped.
Then, the valve 105 is opened and a predetermined gas is
Start of nuclide conversion experiments by introducing deuterium gas at high pressure
I do. Here, a predetermined gas pressure when introducing deuterium gas is used.
The force is regulated by a regulator valve 104, for example
1.01325 × 10 ^FivePa (so-called 1 atm)
(Step S46). Note that the light passes through the multilayer structure 102.
The amount of deuterium that has come out of the discharge container 101 is, for example, a vacuum.
Of vacuum in the discharge container 101 detected by the meter 112
And the pumping speed of the turbo molecular pump 110
Put out.

The temperature of the multilayer structure 102 is returned to normal temperature a predetermined time, for example, several tens of hours after the introduction of the deuterium gas into the storage container 103 is started. Then, the valve 105 is closed to stop the introduction of deuterium gas into the storage container 103, and the vacuum valve 108 is opened to open the storage container 103.
Is evacuated to end the nuclide conversion experiment (step S
47). Then, from the nuclide conversion apparatus 100, the multilayer structure 1
02 is removed and the multilayer structure 102 is subjected to etching treatment with aqua regia to form a solution in which elements existing on the surface of the multilayer structure 102 are dissolved. The solution was subjected to high frequency inductively coupled plasma-mass spectrometry (ICP-M
S: Inductive Coupled Plasma-Mass Spectrometry)
Is applied to perform quantitative analysis of elements present on the surface of the multilayer structure 102 (step S48).

The following are the results of two nuclide conversion experiments performed by the above-described nuclide conversion method according to the present embodiment,
That is, Example 11 and Example 12 when the same experiment was performed twice will be described with reference to Table 3. Table 3 below shows the results of analysis of Example 11 and Example 12 by ICP-MS. In addition, the analysis result of the solution generated by performing the etching treatment with the aqua regia on the multilayer structure 102 before the start of the experiment was used as a comparative example.

[0103]

[Table 3]

As shown in Table 3, in the solution obtained from the multilayer structure 102 before the start of the experiment in the comparative example, the weight of Pr was 0.008 μg, and the weight of Cs was 3.8 μg. This amount of Pr is a detection limit value of the measuring instrument, and is a value as background noise. In contrast, Example 12
In this case, the weight of Pr was 0.12 μg, which was a value sufficiently higher than the background. Further, in Example 11, P
The weight of r is 1.3 orders of magnitude higher than that of Example 12 by about one digit.
μg and the weight of Cs decreased to 2.3 μg. That is, Pr detected in Example 11 and Example 12
Can be concluded as a result of the occurrence of the nuclide conversion reaction from Cs to Pr. In addition, the reaction amount could be increased by increasing the reaction cross-sectional area.

As described above, the nuclide conversion apparatus 100 according to the present embodiment does not require a relatively large-scale device such as a nuclear reactor or an accelerator, and has a relatively small-sized structure. Conversion processing can be performed. Moreover, an experimental result showing that a nuclide conversion reaction from Cs to Pr occurs despite the multilayer structure 102 having an apparatus configuration different from that of the nuclide conversion apparatus 30 according to the first embodiment described above. Can be obtained, and the effectiveness of the essential means of the present invention can be shown.

In the first, second, and third embodiments of the present invention, palladium (Pd) is used as the metal for storing hydrogen. However, the present invention is not limited to this. , Pd alloy or, for example, T
other metals that occlude hydrogen, such as i, Ni, V, Cu,
Alternatively, an alloy of these may be used.

[0107]

As described above, according to the nuclide conversion apparatus of the first aspect of the present invention, it is possible to perform nuclide conversion with a relatively small configuration as compared with, for example, a nuclear reactor or an accelerator. A pressure difference of deuterium is provided between one surface side and the other surface side of the structure, and a flux of deuterium flowing from one surface side to the other surface side is provided inside the structure. By generating, a deuterium conversion reaction can be generated with good reproducibility for deuterium and a substance to be transmuted. further,
According to the nuclide conversion apparatus of the present invention, the occlusion unit is pressurized by the deuterium supply unit, and the discharge unit is depressurized to a vacuum state by the exhaust unit. Can be easily formed.
Furthermore, according to the nuclide conversion apparatus of the present invention described in claim 3, by effectively electrolyzing the electrolytic solution on one surface side of the structure, deuterium can be occluded in the structure with a large pressure effectively. Further, by reducing the pressure of the discharge portion to a vacuum state by the exhaust means, a pressure difference of deuterium can be easily and reliably formed in the structure.

Further, according to the nuclide conversion apparatus of the present invention, the nuclide conversion is carried out on one surface of the structure by a conversion material laminating means, for example, a film forming process such as electrodeposition, vapor deposition, or sputtering. The materials to be applied can be easily laminated. Further, according to the nuclide transmutation device of the present invention as set forth in claim 5, by mixing a substance to be subjected to nuclide conversion into a gas or liquid containing deuterium, a substance to be subjected to nuclide conversion on one surface of the structure. Can be easily contacted. Furthermore, according to the nuclide conversion device of the present invention described in claim 6,
By providing a mixed layer containing a substance having a low work function in a structure having a multilayer structure, reproducibility of generation of a nuclide conversion reaction can be improved. In the nuclide conversion apparatus according to the present invention as set forth in claims 1 to 6, the generation of a nuclide conversion reaction can be promoted by converting a substance to be subjected to nuclide conversion into a nuclide having a similar isotopic composition. In addition, it is possible to improve the reproducibility with respect to the occurrence of the nuclide conversion reaction.

According to the nuclide transmutation method of the present invention, the deuterium flux from one surface side to the other surface side is generated inside the structure, so that the deuterium flux is generated. A nuclide transmutation reaction can be generated with high reproducibility for hydrogen and a substance to be transmuted. Furthermore, according to the nuclide conversion method of the present invention as set forth in claim 8, for example, a substance to be subjected to nuclide conversion is laminated on one surface of the structure by a film forming process such as electrodeposition, vapor deposition, or sputtering, or For example, by mixing a substance to be transmuted into a gas or liquid containing deuterium, the substance to be transmuted can be easily brought into contact with one surface of the structure. Further, according to the nuclide transmutation method of the present invention as set forth in claim 9, the generation of a nuclide transmutation reaction can be promoted by converting a substance to be subjected to nuclide transmutation into a nuclide having a similar isotopic composition. In addition, reproducibility can be improved with respect to the occurrence of a nuclide conversion reaction.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a nuclide conversion method according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram illustrating a structure used in the nuclide conversion method according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a nuclide conversion device according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a multilayer structure used in the nuclide conversion apparatus shown in FIG. 3;

5A is a cross-sectional configuration diagram of a mixed layer, and FIG. 5B is a cross-sectional configuration diagram of a structure including the mixed layer.

FIG. 6 is a configuration diagram of an apparatus for adding a substance to be subjected to nuclide conversion to a structure.

FIG. 7 shows XP on the surface of the multilayer structure shown in FIG.
It is a graph which shows the spectrum of Pr by S.

FIG. 8 shows Cs on the surface of the multilayer structure shown in FIG. 5;
And FIG. 7 is a graph showing the time change of the number of atoms of Pr and Pr.

FIG. 9 is a graph showing the time change of the number of atoms of C, Mg, Si and S on the surface of the multilayer structure in Example 3.

FIG. 10 is a graph showing the time change of the number of atoms of C, Mg, Si and S on the surface of the multilayer structure in Example 4.

FIG. 11 is a sectional configuration diagram showing a multilayer structure 32 according to a second modification of the present embodiment.

12 is a graph showing the spectrum of Mo by XPS on the surface of the multilayer structure shown in FIG. 11;

13 is a graph showing a change over time in the number of atoms of Sr and Mo on the surface of the multilayer structure shown in FIG.

14 is a graph showing a change over time in the number of atoms of Sr and Mo on the surface of the multilayer structure shown in FIG.

FIG. 15 is a graph showing the isotope abundance ratio of naturally occurring Mo along with a change in mass number.

FIG. 16 is a graph showing the isotope abundance ratio of Mo observed on the surface of the multilayer structure together with the change in the mass number in the fifth embodiment.

FIG. 17 is a graph showing the isotope abundance ratio of naturally occurring Sr added as a substance to be subjected to nuclide conversion together with a change in mass number.

FIG. 18 is a diagram illustrating the principle of a nuclide conversion method according to a second embodiment of the present invention.

FIG. 19 is a configuration diagram of a nuclide conversion device according to a second embodiment of the present invention.

20 is a view showing the surface of the multilayer structure on the electrolytic cell side after an experiment using the nuclide conversion apparatus shown in FIG. 19.

21 is a graph showing a result of SIMS analysis of the surface of the multilayer structure after an experiment using the nuclide conversion apparatus shown in FIG.

FIG. 22 is a configuration diagram of a nuclide conversion device according to a third embodiment of the present invention.

[Explanation of symbols]

10, 30, 70, 80, 100 nuclide conversion apparatus 11 structure 21 Pd layer (surface layer) 22 mixed layer 23 Pd substrate (base material) 31 occlusion chamber (occluding section) 32, 89, 102 multilayer structure (structure) 34) Release chamber (discharge unit) 35,106 Deuterium cylinder (high pressure means, deuterium supply means) 38,110 Turbo molecular pump (low pressure means, exhaust means) 39,111 Rotary pump (low pressure means, exhaust means) ) 72 Cathode (structure) 81 Power supply (high pressure means, electrolysis means) 83 Electrolysis cell (occluding part) 84 Electrolytic solution 85 Vacuum container (discharge part) 91 Vacuum exhaust pump (low pressure means, exhaust means) 101 Release container (Release section) 102 Storage container (Storage section)

Continued on the front page (72) Inventor Mitsuru Banno 1-8-1 Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Heavy Industries, Ltd. (72) Inventor Satoshi Sakai 1-8-1, Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries, Ltd. Fundamental Technology Laboratory F-term (reference) 4K021 AB23 BA01 DA09 4K044 AA06 BA08 BB02 BC14 CA13 CA14

Claims (9)

[Claims] 1. A structure made of palladium or a palladium alloy, or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy, and arranged so as to sandwich the structure from both sides, and sealed by the structure An occlusion part and a discharge part which form a possible closed space; and a high-pressure means for setting the occlusion part side, which is one surface side of the structure, to a relatively high deuterium pressure state; A pressure reducing means for setting the discharge portion side, which is the other surface of the structure, to a state in which the pressure of deuterium is relatively low; and a conversion material for contacting a material for performing nuclide conversion on one surface of the structure. A nuclide conversion device comprising: a contact unit. 2. The high pressure means comprises deuterium supply means for supplying deuterium gas to the storage part, and the low pressure means comprises exhaust means for evacuating the discharge part. The nuclide conversion device according to claim 1. 3. The high-pressure means includes: an electrolytic means for supplying an electrolytic solution containing deuterium to the occlusion part to electrolyze the electrolytic solution using the structure as a cathode. The nuclide conversion apparatus according to claim 1, further comprising an exhaust unit that evacuates the discharge unit. 4. The conversion material contacting means according to claim 1, wherein said conversion material contacting means includes a conversion material laminating means for laminating a substance to be subjected to nuclide conversion on one surface of said structure. A nuclide converter according to any one of the above. 5. The conversion material supply means for supplying the storage material with the nuclide conversion material and exposing one surface of the structure to a gas or liquid containing the nuclide conversion material. The nuclide conversion apparatus according to any one of claims 1 to 3, further comprising means. 6. The structure includes a base material made of palladium, a palladium alloy, a hydrogen storage metal other than palladium, or a hydrogen storage alloy other than a palladium alloy, in order from the other surface side to the one surface side. A mixed layer formed on the surface of the base material and made of palladium or a palladium alloy or a hydrogen storage metal other than palladium or a hydrogen storage alloy other than a palladium alloy, and a material having a low work function; and on the surface of the mixed layer And a surface layer formed of palladium, a palladium alloy, a hydrogen storage metal other than palladium, or a hydrogen storage alloy other than the palladium alloy. The nuclide conversion device according to item 1. 7. A structure made of palladium, a palladium alloy, a hydrogen storage metal other than palladium, or a hydrogen storage alloy other than a palladium alloy, has one surface side of the structure relatively deuterium pressure. A high pressure treatment, a low pressure treatment in which the other surface side of the structure has a relatively low pressure of deuterium, and a substance for performing nuclide conversion on one surface of the structure. And a conversion substance contacting process for contacting the nuclide. 8. The conversion material contact treatment may be a conversion material lamination process for stacking a substance to be subjected to the nuclide conversion on one surface of the structure, or the nuclide conversion on one surface of the structure. The nuclide conversion method according to claim 7, further comprising any one of a conversion material supply process of exposing to a gas or a liquid containing a substance to be applied. 9. The nuclide conversion according to claim 7, wherein in the conversion substance contact treatment, the substance to be converted is brought into contact with one surface of the structure. Method.